Objective:

In response to increasing costs of groundwater remediation and more stringent
environmental regulations regarding groundwater pollution, we propose to investigate
another way of reducing the remediation costs under existing remediation technoiogies
through better characterization of contamination sites.

The main objective is to develop a computer-aided visual tool for effectively characterizing groundwater remediation sites by estimating important unknown parameters such as hydraulic conductivity and hydrodynamic dispersivity.

Approach:

Our approach is based on simulation-optimization methodology that processes
available observation data and returns with a site-specific distribution of
unknown characteristic parameters such as hydraulic conductivity or transmissivity.
We use optimization methods and numerical techniques along with groundwater
models. Our major activities will include designing numerical algorithms, writing
computer codes, and testing various programs. Although our model is of analytic
nature, experimental results and expert knowledge of a particular remediation
site are helpful as they can be incorporated into this model through the input
process that our program provides or through interactive user interface of the
model. All the information is then processed by a computer that is controlled
by the user through its visual user interface under the Windows 95 platform.
An estimated optimal site characterization is numerically generated by a sophisticated
computer program instead of the traditional trial-and-error approach. As a result,
it usually identifies a better-calibrated model than any trial-and-error approach
within the same amount of search time.

Expected Results:

We expect two major benefits from the proposed tool. (1). It directly helps
the user to find a well calibrated model that reasonably matches the observed
data. (2). It can be subsequently used in conjunction with other management
models such as DOMODF (cf. Sun and Zheng 1996) to help: (a) identify a remediation
policy that achieves the same remediation goal with much smaller costs than
the currently implemented strategy, (b) find (if there is any) a remediation
policy that meets the same remediation goal more quickly than the currently
implemented strategy. This project directly addresses at least one focus issue
of GCHSRC, that is, groundwater site remediation. In contrast to the development
of hardware remediation technology, our software product can be developed within
a relatively short period of time and with much less development cost. It is
also easier to upgrade or to adjust according to a particular remediation project.
To ensure reliability as well as efficiency, our tool is going to be built on
top of an advanced version of an existing EPA's groundwater simulation code
MT3D developed by the Co-PI (Zheng 1990) along with its companion code MODFLOW
from USGS (McDonald and Harbaugh 1988) by adding several major numerical procedures
that perform various new tasks related to the site characterization problem.
Our approach is fairly technical, but our final tool is going to be user friendly.
The successful completion of this project will add a new effective weapon to
EPA's list of arsenals for combating groundwater remediation battles in many
years to come. Achieving such objectives takes an interdisciplinary team that
possesses analytic skills to do comprehensive modeling, experience in site characterization
and remediation projects to ensure reliability of the product, and computer
equipment and software to implement the proposed methodology.

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.